1. Field of the Invention
The present invention relates to a computational model capable of relating the left ventricular regional myocardial contraction to hemodynamics. The fields of use include cardiovascular and pharmaceutical research, computer assisted instruction in cardiovascular physiology, and planning for cardiac surgery and treatment procedures such as the ventricular restoration surgery Cohn L H. Chen F Y, Cohn L H. The surgical treatment of heart failure. A new frontier: nontransplant surgical alternatives in heart failure. Cardiology Review 10(6): 326-33, 2002. and the cardiac resynchronization therapy Adamson P B, Abraham W T. Cardiac resynchronization therapy for advanced heart failure. Current Treatment Options Cardiovascular Medicine 5(4): 301-309, 2003.
2. Description of the Prior Art
Finite element models are used to simulate behaviors of complex systems. There are many different models for a variety of different systems which are well known to those skilled in the art. Typically the systems are subdivided into interconnected elements that represent sections, in the material and react in such a way that they influence the reaction of their adjacent sections. The finite element model simulates this behavior by solving differential equations for each of the elements that represents a relatively small section in the material.
For the study of the mechanics of the myocardium of the left ventricle, several models based on finite element methods have been used in the past. Bovendeerd P H M, Arts T, Delhaas T, Huyghe J M, van Campen D H, Reneman R S. American Journal of Physiology 270: H398-H410, 1996 used a finite element model accounting for the thick-walled ventricular geometry to simulate the ischemic left ventricle during a complete cardiac cycle. Their model significantly over estimated (by about double) the loss of stroke work. Ratcliffe M B, Hong J, Salahieh A, Ruch S, Wallace A W. The effect of ventricular volume reduction surgery in the dilated, poorly contractile left ventricle: a simple finite element analysis. Journal of Thoracic Cardiovascular Surgery 116(4): 566-77, 1998 used a finite element analysis for the effect of ventricular volume reduction surgery. Their model predicted the left ventricular dynamics at end of systole and end of diastole, not for the entire cardiac cycle. Guccione J M, Moonly S M, Moustakidis P, Costa K D, Moulton M J, Ratcliffe M B, and Pasque M K. Mechanism underlying mechanical dysfunction in the border zone of left ventricular aneurysm: A finite element model study. Annals of Thoracic Surgery 71: 654-662, 2001 used a finite element model to characterize the mechanics of the border zone region of left ventricular aneurysm. Their model representation was also limited to the end-systolic and end-diastolic time instances. All the aforementioned models were focused on the left ventricle only and did not include a comprehensive representation of the circulatory system.
Sun Y, Beshara M., Lucariello R J, Chiaramida S A. A comprehensive model for right-left heart interaction under the influence of pericardium and baroreflex. American Journal of Physiology 272: H1499-H1515, 1997 developed a comprehensive analog electrical model to characterize the hemodynamics during heart failure and the right-left heart interaction under the influence of pericardium and baroreflex. While the analog circulatory model was capable of generating realistic and physiological pressure and flow waveforms at various parts of the cardiovascular system, it did not have a three-dimensional description of the left ventricular walls. Therefore, this model was incapable of relating regional impairment of left ventricular myocardium to its global effect on the hemodynamics of the entire cardiovascular system.